The present invention relates in general to a waste gas recovery system.
It is well known to burn off or discharge waste gas arising in process plants used in the oil and chemical industries. Normally, the waste gas is passed to a flare which is elevated and is burnt off at the top of the flare. Nowadays, there is a tendency to utilize recovery systems which process waste gas for utilization as a fuel. There is, however, a need for a flexible recovery system which can be easily integrated with existing plant equipment on site. The recovery system would supplement the normal flare system so that the latter would still operate in abnormal emergency conditions where there is a need to dispose of a large quantity of waste gas. The normal flare system or the recovery system would employ control means to ensure that the waste gas diverted from the flare system for recovery purposes would not be such as to cause air to be drawn into the flare system, thereby creating a dangerous situation. Since the pressure and flow rates of the waste gas can vary over wide ranges in a typical plant, the recovery system should be adapted to cope with such expected variations. Above all, the systems must ensure that the waste gas recovery is achieved in a safe, reliable manner and without adversely affecting the normal flare system. A general object of the present invention is to provide an improved form of recovery system.